This invention relates generally to gas turbine engines and more particularly, to combustor assemblies for use with gas turbine engines.
At least some known gas turbine engines use cooling air to cool a combustion assembly within the engine. Moreover, often the cooling air is supplied from a compressor coupled in flow communication with the combustion assembly. More specifically, in at least some known gas turbine engines, the cooling air is discharged from the compressor into a plenum extending at least partially around a transition piece of the combustor assembly. A first portion of the cooling air entering the plenum is supplied to an impingement sleeve surrounding the transition piece prior to entering a cooling channel defined between the impingement sleeve and the transition piece. Cooling air entering the cooling channel is discharged into a second cooling channel defined between a combustor liner and a flowsleeve. The remaining cooling air entering the plenum is channeled through inlets defined within the flowsleeve prior to also being discharged into the second cooling channel.
Within the second cooling channel, the cooling air facilitates cooling the combustor liner. At least some known flowsleeves include inlets and thimbles that are configured to discharge the cooling air into the second cooling channel at an angle that is substantially perpendicular to the flow of the first portion of cooling air entering the second cooling chamber. More specifically, because of the different flow orientations, the second portion of cooling air loses axial momentum and may create a barrier to the momentum of the first portion of cooling air. The barrier may cause substantial dynamic pressure losses in the air flow through the second cooling channel.
At least one known approach to decreasing the amount of pressure losses requires resizing the inlets in the existing system. However, this approach may require multiple inlets to be resized at multiple sections of the engine. As such, the economics of this approach may outweigh any potential benefits.